Edit report at https://bugs.php.net/bug.php?id=46600&edit=1
ID: 46600
Updated by: bukka@php.net
Reported by: Matt at mpcm dot com
Summary: "_empty_" key in objects (see #41504)
Status: Re-Opened
Type: Feature/Change Request
Package: JSON related
Operating System: *
PHP Version: irrelevant
-Assigned To:
+Assigned To: bukka
Block user comment: N
Private report: N
New Comment:
Nikita has already sent a patch to allow empty property names in object. I will be happy to provide
json part if that patch is merged.
Previous Comments:
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[2016-03-25 03:38:12] matt at mpcm dot com
Yasuo, thank you for the response.
Blank keys in json are a relatively common thing to encounter.
I do agree, not all languages offer access to "", especially within traditional concept of
a predefined class and named property.
But... it feels like PHP should be able to handle this. Since we already have leading
space properties working...
I think the real fix (or feature request) for this bug, is that json_decode should not be returning
stdClass at all.
But something that extends stdClass, with a __get/__set to handle non-valid property strings that
are valid json keys.
Paired with undoing "" to "_empty_", this would essentially remove the issue
entirely.
Maybe that add's even more complications to php that I'm not considering ?
Are there other keys that come to mind, or things that php also remaps, besides "" to
"_empty_" ?
I'll take a look at the newer php constructs this weekend, to see if there is an easier way
around this now.
I haven't looked into the issue recently, but in the past I used something like the below to
allow object style access.
https://gist.github.com/mpcm/2ce3687b121fdd13e2a8#file-jsonobject-class-php-L2
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[2016-03-23 22:36:15] yohgaki@php.net
I fully agree empty string is valid unicode string.
The RFC does not mention validity of empty object property which is invalid in most languages.
There is nothing we can do for this because object property name cannot be "". Any
restrictions to property name apply as well for objects.
However, we can cast object to array, array to object.
[yohgaki@dev ~]$ php -n -r '$a = [""=>1]; $o = (object)$a; var_dump($o); $a =
(array)$o; var_dump($a);'
object(stdClass)#1 (1) {
[""]=>
int(1)
}
array(1) {
[""]=>
int(1)
}
It may be better to remove automatic "" -> "_empty_" conversion at some
point. e.g. next minor release.
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[2016-03-23 12:17:38] matt at mpcm dot com
Looking at that same doc:
https://tools.ietf.org/html/rfc7159#section-1
"A string is a sequence of zero or more Unicode characters [UNICODE]."
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[2016-03-23 07:43:13] yohgaki@php.net
Property names are defined as "string" and "string" is defined as follows.
https://tools.ietf.org/html/rfc7159#section-7
string = quotation-mark *char quotation-mark
char = unescaped /
escape (
%x22 / ; " quotation mark U+0022
%x5C / ; \ reverse solidus U+005C
%x2F / ; / solidus U+002F
%x62 / ; b backspace U+0008
%x66 / ; f form feed U+000C
%x6E / ; n line feed U+000A
%x72 / ; r carriage return U+000D
%x74 / ; t tab U+0009
%x75 4HEXDIG ) ; uXXXX U+XXXX
escape = %x5C ; \
quotation-mark = %x22 ; "
unescaped = %x20-21 / %x23-5B / %x5D-10FFFF
https://tools.ietf.org/html/rfc7159#section-4
Object property name should be unique. i.e. "The names within an object SHOULD be unique."
I cannot tell if "" is valid or not. Is it valid JSON?
BTW, the name for empty elements should be "__empty" or "__empty__" as we
usually "__name" or "__name__" for reserved names.
------------------------------------------------------------------------
[2016-03-23 02:49:25] ofbeaton at gmail dot com
So I just ran into this problem while making a satis repository script for composer. I don't
see a good solution.
If I $composerJson = json_decode($composerJson, true) into associative arrays,
manipulate it, then json_encode($composerJson) then my
"require-dev": {}
turns into
"require-dev": []
which composer chokes on. So obviously I can't read the composer file as associative arrays!
That isn't this bug, I just want to show upfront that using the associative array parameter on
my json_decode cannot solve my problem.
So I do: $composerJson = json_decode($composerJson, false) and turn it into objects
like this thread talks about. Except the most common composer.json contains something like this:
"autoload": {
"psr-4": {
"": "src/"
}
}
it reads it in fine, but when I do json_encode($composerJson) again... I get:
"autoload": {
"psr-4": {
"_empty_": "src/"
}
}
which composer then chokes on because of course "_empty_" has a different meaning than
"".
So I'm stuck doing a json_encode then using a hack, $composerJson =
str_replace('"_empty_":', '"":', $composerJson)
before writing it to file again.
The _empty_ key does not seem to me to be the right answer here. Should composer change the way
composer files for virtually all projects be written? Is this a composer bug?
Or should json_encode and json_decode objects reproduce a blank key?
I hope the answer is the later, but I cannot say for sure.
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